package cn.webestar.scms.security.captcha;

import org.springframework.stereotype.Service;

import java.awt.*;
import java.awt.image.BufferedImage;
import java.util.Random;

@Service
public class ImageCaptchaGenerator {

    public static final String CAPTCHA_CHAR_SET = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789abcdefghijklmnopqrstuvwxyz";

    public ImageCaptcha generate() {
        int width = 60;
        int height = 20;
        BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
        Graphics g = image.getGraphics();
        Random random = new Random();
        g.setColor(getRandColor(200, 250));
        g.fillRect(0, 0, width, height);
        g.setFont(new Font("Times New Roman", Font.ITALIC, 20));
        g.setColor(getRandColor(160, 200));
        for (int i = 0; i < 155; i++) {
            int x = random.nextInt(width);
            int y = random.nextInt(height);
            int xl = random.nextInt(12);
            int yl = random.nextInt(12);
            g.drawLine(x, y, x + xl, y + yl);
        }
        StringBuffer sb = new StringBuffer();
        for (int i = 0; i < 4; i++) {
            String rand = CAPTCHA_CHAR_SET.charAt(random.nextInt(CAPTCHA_CHAR_SET.length())) + "";
            g.setColor(new Color(20 + random.nextInt(110), 20 + random.nextInt(110), 20 + random.nextInt(110)));
            g.drawString(rand, 13 * i + 6, 16);
            sb.append(rand);
        }
        g.dispose();
        return new ImageCaptcha(image, sb.toString(), 60);
    }

    private Color getRandColor(int fc, int bc) {
        Random random = new Random();
        if (fc > 255) {
            fc = 255;
        }
        if (bc > 255) {
            bc = 255;
        }
        int r = fc + random.nextInt(bc - fc);
        int g = fc + random.nextInt(bc - fc);
        int b = fc + random.nextInt(bc - fc);
        return new Color(r, g, b);
    }

}
